Spray nozzle for gas scrubbers

ABSTRACT

A liquid spray nozzle which includes a pair of concentric tubular members. Liquid to be sprayed is supplied to the outer tubular member and compressed gas is supplied to the inner tubular member. The outer tubular member includes a reducer portion followed by an expander portion. The liquid and gas mix in the reducer portion and the liquid-gas mixture is discharged from the nozzle through the expander portion. The nozzle is particularly designed for use with a gas scrubber and is positioned in the flow path of the gas to be cleaned as it passes from the dirty gas inlet to the clean gas outlet. The liquid spray is countercurrent to the flow of gas to be cleaned.

United States Patent Lincoln 1 Sept. 19, 1972 [541 SPRAY NOZZLE FOR GASSCRUBBERS [72] Inventor: Roland L. Lincoln, Salvang, Calif.

[73] Assignee: Fuller Company [22] Filed: Nov. 19, 1970 [21] Appl. No.:91,089

[52] US. Cl. ..239/4l9, 239/430, 239/4345 [51] Int. Cl. ..B05b 7/04 [58]Field of Search ..239/398, 419, 552, 429, 430, 239/4345 [56] ReferencesCited UNITED STATES PATENTS 2,795,461 6/1957 Durkin ..239/434.5 X

1 ,748,604 2/1930 l-leimburger ..239l434.5

2,769,670 11/1956 Dunn ..239/398 X 2,447,123 8/1948 Jones ..239l430 X1,751,719 3/ 1930 Uhri ..239/434.5 X

2,672,190 3/1954 Schumann ..239/4l9 X 1,592,865 7/1926 Moxley..239/434.5 X

1,102,751 7/1914 Hicks ..239/430 X 1,519,462 12/1924 boker ..239/430894,069 7/1908 Schurs ..239/434.5 3,455,514 7/1969 Fenley..... ..239/419Primary Examiner-M. Henson Wood, Jr. Assistant Examiner--Edwin D. GrantAttorney-Jack L. Prather and Frank 11. Thomson [57] ABSTRACT A liquidspray nozzle which includes a pair of concentric tubular members. Liquidto be sprayed is supplied to the outer tubular member and compressed gasis supplied to the inner tubular member. The outer tubular memberincludes a reducer portion followed by an expander portion. The liquidand gas mix in the reducer portion and the liquid-gas mixture isdischarged from the nozzle through the expander portion. The nozzle isparticularly designed for use with a gas scrubber and is positioned inthe flow path of the gas to be cleaned as it passes from the dirty gasinlet to the clean gas outlet. The liquid spray is countercurrent to theflow of gas to be cleaned.

2 Claims, 4 Drawing Figures PATENTEDsEP 19 I972 3.692.244

, s s V i i INVENTOR i ,E' ROLAND: L. L/NCOL/V FIG. 4 W fiVA ATTORNEYSPRAY NOZZLE FOR GAS SCRUBBERS BACKGROUND OF THE INVENTION The presentinvention relates to liquid spray nozzles and in particular to a liquidspray nozzle designed for use with a gas scrubber. The nozzle isparticularly designed for use with the gas scrubber shown in my priorcopending U. S. Pat. Application, Ser. No. 30,670, filed Apr. 22, 1970,now US. Pat. No. 3,651,620.

Most gas scrubbers presently commercially available are of theVenturi-type in which the dirty gas to be cleaned is accelerated to ahigh velocity by being passed through a Venturi. Scrubbing water isintroduced into the high velocity gas in order to clean the gas. In suchscrubbers, the high energy contact between the scrubbing water and thedirty gas is achieved by the acceleration of the dirty gas. Such highenergy contact is necessary for efficient collection of the dustparticles in the dirty gas. In my prior, copending U. S. Pat.Application, Ser. No. 30,670, filed Apr. 22, 1970, I disclose a novelgas scrubber in which the high energy contact is achieved by puttingmost of the energy into the water which in introduced into the flow ofdirty gas. This is accomplished by using gas such as air at elevatedpressure to spray the scrubbing liquid.

In order for the scrubber shown and described in my prior, above mentionpatent application to properly clean the dirty gas, it is essential thatthe scrubbing liquid be adequately atomized, have a high velocity inorder to achieve high energy contact, have a spray envelop theconfiguration of which covers the full gas stream and supply a largevolume of liquid. By the present invention, I have provided a liquidspray nozzle which satisfactorily performs these functions.

Prior to the present invention, spray nozzles often employed mechanicalatomization of the liquid by pumping the liquid through an orifice. Withsuch an arrangement, it is difficult to impart to the water the highenergy necessary for the proper operation of the gas scrubber of myaforementioned applications, without the use of either very smallorifices which tend to plug or excessive water quantities. An additionalproblem with such arrangements is that complete atomization and properspray direction is not always achieved.

Prior spray nozzles which employ gas at an elevated pressure to spraythe liquid have been found to be unsatisfactory in achieving properatomization and spray pattern. An additional problem encountered withprior spray nozzles which employ air at elevated pressure to atomizeliquid is that the air must be at pressures of 50 psig and higher whichrequire the use of a multistage compressor. In gas scrubber use, itwould be desirable to be able to operate with lower pressures; such as30 psig to use single stage compressors or to psig which can be achievedwith a blower. It would also be desireable to have a nozzle which iscapable of operating efficiently with the use of either high or lowpressure air.

For many applications of spray nozzles and particularly nozzles for usewith wet scrubbers, the water spray must cover a wide area and theremust be complete water coverage within the outer periphery of the sprayenvelope. Many prior spray nozzles provide a large spray envelope, butwater is atomized only around the outer periphery of the spray envelope.

Spray nozzles which are to be used with gas scrubbers must be capable ofatomizing large quantities of water. The nozzle of the present inventionis designed to atomize liquid at flow rates up to 200 gallons per minuteand more.

An additional requirement of spray nozzles for many applications is thatthey must be capable of atomizing liquids which contain particulatematter without becoming plugges. This is particularly important inapplications where unfiltered water is to be used.

SUMMARY It is, therefore, the principal object of this invention toprovide a novel liquid spray nozzle which overcomes the disadvantages ofprior spray nozzles.

It is another object of this invention to provide a liquid spray nozzlewhich is capable of atomizing large quantities of liquid.

It is a further object of this invention to provide a liquid spraynozzle which is particularly adapted for use with a gas scrubber whereinmost of the energy required for cleaning the gas is imparted to thescrubbing liquid.

It is still a further object of this invention to provide a liquid spraynozzle which is capable of atomizing an unfiltered liquid withoutbecoming plugged.

In general, the foregoing and other objects of this invention will becarried out by providing a nozzle for spraying liquids comprising firsttubular means defining a continuous liquid flow passage; said firsttubular means having internal walls which define a first longitudinalportion having a substantially constant cross-sectional area; a secondlongitudinal portion having a substantially continuously decreasingcross-sectional area; and a third longitudinal portion having asubstantially continuously increasing cross-sectional area whichterminates in an open end; a second tubular means extending into saidfirst tubular means and defining a flow passage for gaseous fluid whichterminates in an open end with said first tubular means; means forsupplying liquid to be sprayed to said first tubular means; and meansfor supplying gaseous fluid at elevated pressure to said second tubularmeans whereby the gaseous fluid mixes with said liquid within said firsttubular means and the mixture is discharged from the nozzle through theopen end of said third portion.

BRIEF DESCRIPTION OF THE DRAWING The invention will be described inconnection with the annexed drawing wherein:

FIG. 1 is a diagrammatic view of a gas scrubber which employs the nozzleof the present invention;

FIG. 2 is a sectional view of the liquid spray nozzle of the presentinvention;

FIG. 3 is a fragmentary sectional view on an enlarged scale taken on theline 3-3 of FIG. 2; and

FIG. 4 is a fragmentary sectional view of a-modification of the presentinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention will be describedas it is used with a gas scrubber, but it .is intended that the spraynozzle of the present invention be applicable wherever it is desired toachieve good atomization of a large quantity of liquid. The nozzle ofthe present invention is particularly applicable for use with the gasscrubber shown and described in my copending U. S. Pat. Application Ser.No. 30,670, filed Apr. 22, 1970.

Referring to FIG. 1, the gas scrubber of the above mentioned copendingapplication is schematically shown. The scrubber includes a housing 1having a dirty gas inlet 2 and a clean outlet 3. The housing is dividedby means of a plate 5 having a column 6 vertically mounted therein. Thebottom of the housing 1 provides a liquid reservoir 8 having a drain 9.

The liquid spray nozzle of the present invention is generally indicatedat 20 and is adapted to spray liquid up into the column 6. Liquid fromthe reservoir 8 is circulated through a conduit 11, pump 12 and conduit13 to the nozzle 20. Gas at an elevated pressure is supplied from asource 15 such as a compressor or a blower through a conduit 16 to thenozzle 20.

In operation, dirty gas enters the housing 1 through inlet 2 and passesthrough column 6 at a velocity. Liquid is sprayed by nozzle up into thecolumn 6 in a direction counter-current to the flow of dirty gas. UnlikeVenturi-type gas scrubbers, the high energy necessary for efficient gascleaning is imparted to the scrubbing liquid rather than to the flow ofdirty gas. The liquid spray cleans the dirty gas in a manner well knownin the gas scrubber art. Cleaned gas is exhausted from housing 1 throughoutlet 3. A conduit 17 is provided in the plate 5 to drain any liquidwhich reaches the chamber above the plate 5 back into the reservoir 8The nozzle of the present invention is best illustrated I in FIGS. 2 and3. The nozzle 20 includes a first tubular means 21 which includes afirst longitudinal portion 22 having a substantially constantcross-sectional area. The tubular means 21 has an inlet conduit 24 whichis adapted to be connected to a source of liquid to be sprayed such asconduit 13. Downstream of the inlet conduit 24 is a reducer or secondlongitudinal portion 26 which is shown as a truncated cone having curvedsidewalls having a substantially continuously decreasing cross-sectionalarea. It should be understood, that the reducer 26 may have straightconical walls. The important feature is that the walls defining asubstantially, continuously restricting flow passage. The downstream endof the reducer portion 26 is provided with straight sides 27.

A spray director means generally indicated at 28 and having a flowpassage 30 therethrough is mounted on the reducer portion 26 in coaxialalignment with the reducer 26 and first longitudinal portion 22. Thespray director means is mounted on the first tubular member by means ofan annular plate 32 and threaded rods 33 as clearly shown in FIG. 2. Theflow passage 30 includes a longitudinal portion 34 having a constantcross-sectional area V and a divergent longitudinal portion 35. Thelargest diameter of the divergent portion 35 is preferably smaller thanthe full diameter of the portion 22.

A second tubular means is mounted concentrically within the firsttubular means 21. The member 40 is mounted-in tubular means 21 by meansof a plate 42 which closes tubular means 21, a threaded sleeve 44 and apipe cap 46 having an O-ring seal 47. The tubular means 40 is threadedas at 48 to permit longitudinal adjustment of the second tubular means40 within the tubular means 21, The tubular member 40 is adapted to beconnected to the conduit 16 and the source of gas at elevated pressure15. Preferably, the second tubular means terminates at the beginning ofthe reducer portion 26 so that a mixing chamber 50 is defined within thereducer 26.

For high pressure applications in the compressor range of about 30 psig,member 40 is closed by a plate 52 having a plurality of orifices 54therethrough. The longitudinal axes of the orifices 54 should besubstantially parallel with the longitudinal axis of the second tubularmember 20 and the flow passage 30. For low pressure operations, i.e. inthe blower range of 10 to 15 psig, the passage in the tubular member 40may be left open as shown in FIG. 4.

In operation of the nozzle, large quantities of liquid to be sprayed issupplied from the pump 12 through conduit 13 to inlet conduit 24 and thefirst tubular means 21. The liquid rises in the first tubular portion 22into the mixing chamber 50. Gas at elevated pressure is supplied fromthe source 15 through conduit 16 into the second tubular member 40 whereit passes through the opening inthe end of tubular member 40 into themixing chamber 50. The mixture is forced through flow passage 30 and outthe spray director 28 into the column 6 of the gas scrubber. The spraydirector and in particular the divergent portion 35 serves to insured aproper spray envelope which is of sufficient width to cover the entirecolumn 6 of the scrubber. The spray envelope is not only wide but alsoliquid is atomized throughout the full periphery of the envelope. Thisinsures that all dirty gas is contacted with water. The reducer portion26 serves to aid in the atomization of the liquid.

In some applications, it may be desirable to adjust the relative portionof the outlet of the tubular member 40 within the first tubular means21. If the outlet is moved upwards from the position shown in FIG. 2, adifferent spray pattern will be achieved. It is believed that the amountof atomization of the liquid will be altered.

From the foregoing it should be apparent that the objects of the presentinvention have been carried out. The spray nozzle can be used witheither high pressure gas by employing the plate 52 or with low pressuregas by leaving the flow passage in tubular means 40 open. The energy isimparted to the liquid by the use of gas at elevated pressured ratherthan by a high pressure pump. This is particularly important when dirtywater is being used, as dirty water presents problems with high pressurepumps. The spray director 28 insures a proper spray envelope which isparticularly important for use in gas scrubber applications. The openflow passage design of the nozzle permits large quantities of unfilteredliquid to be sprayed. This is particularly important with the gasscrubber shown since dirty water is recirculated.

It is intended that the foregoing description be merely that of apreferred embodiment and that the invention be limited solely by thatwhich is within the scope of the appended claims.

Iclaim:

1. For use in combination with a gas scrubber having an inlet forsupplying a gas to be cleaned and an outlet for cleaned gas, a nozzlefor spraying scrubbing liquid into the dirty gas in a direction oppositeto the flow of gas to be cleaned comprising:

a first tubular member;

means for supplying scrubbing liquid to said first tubular member;

said first tubular member having a portion downstream of said supplymeans which defines a substantially continuously restricting flowpassage;

spray director means mounted on said first tubular member and having aflow passage therethrough having a portion downstream of the restrictingflow passage of said first tubular member having divergent walls whichterminate in an open end;

a second tubular member mounted within said first tubular member anddefining a flow passage therethrough which terminates within said firsttubular member;

means for supplying gas at an elevated pressure to said second tubularmember whereby the gas mixes with the scrubbing liquid and the mixtureis discharged through the open end of said spray director means into theflow of gas to be cleaned in a volume and at a velocity sufficient toclean the gas to be cleaned; and

plate means having a plurality of orifices therethrough covering theflow passage through said second tubular member;

the longitudinal axes of said orifices being substantially parallel withthe longitudinal axis of the first tubular member.

2. The combination of claim 1 wherein said second tubular member iscoaxially mounted within said first tubular member and extends into saidfirst tubular member at least as far as said portion of said firsttubular member which defines a substantially continuously restrictingflow passage.

1. For use in combination with a gas scrubber having an inlet forsupplying a gas to be cleaned and an outlet for cleaned gas, a nozzlefor spraying scrubbing liquid into the dirty gas in a direction oppositeto the flow of gas to be cleaned comprising: a first tubular member;means for supplying scrubbing liquid to said first tubular member; saidfirst tubular member having a portion downstream of said supply meanswhich defines a substantially continuously restricting flow passage;spray director means mounted on said first tubular member and having aflow passage therethrough having a portion downstream of the restrictingflow passage of said first tubular member having divergent walls whichterminate in an open end; a second tubular member mounted within saidfirst tubular member and defining a flow passage therethrough whichterminates within said first tubular member; means for supplying gas atan elevated pressure to said second tubular member whereby the gas mixeswith the scrubbing liquid and the mixture is discharged through the openend of said spray director means into the flow of gas to be cleaned in avolume and at a velocity sufficient to clean the gas to be cleaned; andplate means having a plurality of orifices therethrough covering theflow passage through said second tubular member; the longitudinal axesof said orifices being substantially parallel with the longitudinal axisof the first tubular member.
 2. The combination of claim 1 wherein saiDsecond tubular member is coaxially mounted within said first tubularmember and extends into said first tubular member at least as far assaid portion of said first tubular member which defines a substantiallycontinuously restricting flow passage.